I can see the benefit of trading Plouffe or moving Sano. Honestly, it's going to come down to where there are openings when Sano is ready. Right now, Sano hasn't given much indication showing he's ready. He's south of the Mendoza line, though he's hitting home runs and drawing walks. I'm hoping that's just rust and the switch will flip here soon, but let's pretend for a second that Sano catches fire, gets sent to Rochester, and continues to rake there... Come 2016, do you put Sano in the OF knowing that Arcia, Buxton, Rosario, and quite possibly Hicks are all competing for time there, or do you trade someone (probably Plouffe)? Do you extend him with a trade in mind? Do you wait another year and slowly work Sano in?
I think Plouffe would get a top 100 prospect, and possibly some others thrown in (assuming he hits well this season). I'd think long and hard about that. He's not a star, but you could pencil him in as a starter on a lot of teams, including quite a few playoff contenders.